Natural Sciences Grade nine : Forces- 111

forces

1. Natural Sciences Grade 9 Forces

2. What is a force? A force is a push or a pull on an object. The unit in which we measure force is a newton (N).

3. Effects of forces Forces can change the shape of an object. This is called deformation . Forces can change the motion of an object. If an object is stationary, a force can cause the object to start moving. Or, if an object is already moving, a force can cause an object to speed up or slow down. Forces can change the direction in which an object is moving.

4. Types of forces

5. There are two types of forces 1. Contact forces – today’s main focus. 2. Non-contact (field) forces

6. 1. CONTACT FORCES Contact forces- objects are in contact with each other and exert forces on each other.

7. Contact forces - Friction is the force which opposes the motion. Friction forces always act in the opposite direction to the motion of the object. Friction resists movement when the object and surface are in contact.

8. Contact forces - Tension is the pulling force that is transmitted through a string, rope, cable, or similar object when it is stretched by forces acting from opposite ends.

9. Contact forces - A compression force is a force which acts to deform or squash an object.

10. THANK YOU!